Using single‐source precursor route, this work reports the synthesis of the novel chalcogenide heterosystem, i.e., BaS:CoS:La2S3 trichalcogenide heterosystem. With the narrowed band gap energy, BaS:CoS:La2S3 expresses excellent photonic response with 3.47 eV of tailored band gap resulting from chemical synergism. This chalcogenide is marked by superior crystallinity and possessed an average crystallite size of 18.29 nm. Morphologically, BaS:CoS:La2S3 exists in the form of the roughly spherical grains arranged in the irregular manner. The developed chalcogenide is assessed for charge storage by fabricating the electrode using a nickel form as a support. In a 0.1 m KOH background electrolyte, the BaS:CoS:La2S3 adorns electrode excelled in achieving a specific capacitance of 967.24 F g−1. In addition, this trichalcogenide expresses the specific power density of 1659 W kg−1. Fabricated electrode retains original capacitance after different cycles. Regarding electrode–electrolyte interactions, the fabricated electrode shows minimal resistance, with an equivalent series resistance (Rs) of 1.42 Ω as indicated by impedance studies. Additional circuit elements, including CPE (Yo = 2.17 × 10−04, n = 0.71) and Rct (6.97 Ω cm−2), are obtained after circuit fitting for the BaS:CoS:La2S3 trichalcogenide decorated electrode. Exhibiting stable behavior for 43 h, the synthesized material demonstrates profound durability and functionality.